The present invention relates to a process for producing pitch carbon fibers.
Pitch carbon fibers have been produced by subjecting pitch fibers obtained by melt-spinning a carbonaceous pitch to infusiblization treatment and then to carbonization treatment or both carbonization treatment and subsequent graphitization treatment. In carbonization, however, there arises the problem that fibers adhere to each other although the adhesion is to a slight extent and consequently the interfiber separability of carbonized or graphitized fibers deteriorates. This problem has not been fully solved yet.
In the production of polyacrylonitrile carbon fibers, it is reported in Japanese Patent Publication No. 12739/1976 that a long-chain silicone oil is imparted to precursors or flameproof fibers. And various silicone oils are mentioned therein as examples of such long-chain silicone oil. However, these silicone oils exhibit no effect in the production of pitch carbon fibers.